Idiocy is the most severe form of mental retardation. Speech patients are missing, they emit only inarticulate sounds. Emotional reactions are expressed only in the sense of pleasure or displeasure: senseless laughter, squealing, agitation, aggressiveness. Often the patients incontinence of urine and feces. There are no and can not be developing the elementary skills of self-service.
Patients require full of care and supervision.

Idiocy is the most severe form of mental retardation. Mental symptoms when idiocy either absent or very poor. Reaction to external irritation sharply reduced. The perception of the external world is very poor, not differentiated. The recognition of other people, household items, extremely limited. Deep idiots do not distinguish edible from inedible. Speech of such patients is missing, they make a separate inarticulate sounds, addressed to them perceive it more in tone than in meaning. Attention difficult to attract. Affective manifestations usually associated with hunger, fear, anger; sexual attraction is sometimes raised. Some patients are lethargic, apathetic, sedentary, other musculoskeletal excited, angry, prone to destructive actions, aggression (bite myself and others). Expression stupid, pointless. Motor sphere sharply defective, patients unable to walk and stand, not master the basic motor skills, but know how to dress, some need to be fed. Many are marked stereotypical pendulum-like rhythmic swaying. Sometimes there is a sharp motor excitation. In most cases, patients untidy. In milder forms of idiocy patients start to walk, acquire skills of neatness, say single words, understand the purpose of some household items, perform elementary instructions, selective affection. Yet the understanding of the surrounding them are not available, they remain completely helpless and require constant care and supervision.